Luminaires with automated and remotely controllable functionality are well known in the entertainment and architectural lighting markets. Such products are commonly used in theatres, television studios, concerts, theme parks, night clubs and other venues. A typical product will provide control over the functions of the luminaire allowing the operator to control the intensity and color of the light beam from the luminaire that is shining on the stage or in the studio. Many products also provide control over other parameters such as the position, focus, beam size, beam shape and beam pattern. In products that contain light emitting diodes (LEDs) to produce the light output, it is common to use more than one color of LEDs and to be able to adjust the intensity of each color separately such that the output, which comprises the combined mixed output of all LEDs, can be adjusted in color. For example, such a product may use red, green, blue, and white LEDs with separate intensity controls for each of the four types of LEDs. This allows the user to mix almost limitless combinations and to produce nearly any color they desire.
FIG. 1 illustrates a typical multiparameter automated luminaire system 10. These systems typically include a plurality of multiparameter automated luminaires, 12 which typically each contain on-board a light source (not shown), light modulation devices, electric motors coupled to mechanical drive systems, and control electronics (not shown). In addition to being connected to mains power either directly or through a power distribution system (not shown), each automated luminaire 12 is connected in series or in parallel to data link 14 and to one or more control desks 15. The luminaire system 10 is typically controlled by an operator through the control desk 15.
Luminaires have been provided using non-LED light sources designed to produce a single narrow beam or a plurality of such beams. Such luminaires may use low etendue, High Intensity Discharge (HID) light sources with a small arc gap in order to facilitate the production of tight, almost parallel light beams. U.S. patent application Ser. Nos. 14/042,758 and 14/042,759 provide examples of such a system. Single and multi-color LED sourced luminaires have also been produced with narrow beam capability using sophisticated collimation systems as, for example, disclosed in U.S. patent application Ser. No. 14/405,355. LEDs however are high etendue light sources by comparison with HID and it is difficult to produce multiple beam systems using LED light sources.
Prior art optical systems utilizing multiple LED emitters may be unforgiving when it is desired to produce a homogeneous image with a light output capable of being blended between units to provide seamless coverage. This mode of operation is often called a wash light as it washes the stage with light. Prior art systems will commonly utilize multiple LED light sources and attempt to blend them into a homogeneous whole. This approach is often unsuccessful because the individual differently colored LED emitters are still visible producing a multi-colored effect when viewing the light rather than the desired appearance of a single color. Other prior art systems use a secondary lens but that has the drawback that the output lens may not then be filled completely and all the light will appear to be emitted from a portion at the centre of the output lens. This reduces the performance of the luminaire as a wash light as it is an important feature of wash luminaires that the effective light source be as large as possible in order to soften and reduce shadowing.
There is a need for a method for producing and controlling a light beam or multiple light beams from an LED sourced wash light luminaire to produce controllable lighting effects from a luminaire with a wash light distribution with a large effective source and true blending output distribution.